WAUSAU, Wis. -- Water experts said torrential rains that ransacked southern Wisconsin in early June are causing problems at swimming beaches as the long Fourth of July weekend approaches.

Bob Masnado, of the state Department of Natural Resources, said the flooding dumped rich nutrients into the lakes, creating ideal conditions for potentially toxic blue-green algae.

The Madison-Dane County Health Department said nine of 15 public swimming beaches in Madison were closed this week.

Masnado said the DNR does not monitor closings for the nearly 1,000 beaches on inland lakes in the state. That is done by local health departments.

He has advised people with water-related recreation plans in flooded areas to call the local health department to find out whether water levels are safe and if there are indications of a health risk.

The DNR said all 190 public beaches along Lake Michigan and Lake Superior were open late this week.